CVE-2008-3971 in gmanedit
Summary
by MITRE
Heap-based buffer overflow in the open_man_file function in callbacks.c in gmanedit 0.4.1 allows remote attackers to execute arbitrary code via a crafted man page, which is not properly handled during utf8 conversion. NOTE: another overflow was reported using a configuration file, but that vector does not have a scenario that crosses privilege boundaries.
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Analysis
by VulDB Data Team • 10/08/2018
The vulnerability identified as CVE-2008-3971 represents a critical heap-based buffer overflow within the gmanedit 0.4.1 documentation editor application. This flaw exists specifically within the open_man_file function located in the callbacks.c source file, creating a dangerous condition that can be exploited by remote attackers to execute arbitrary code on affected systems. The vulnerability stems from inadequate handling of utf8 character encoding during the processing of man pages, which allows maliciously crafted input to overflow memory buffers and potentially compromise system integrity.
The technical implementation of this vulnerability demonstrates a classic heap overflow scenario where the application fails to properly validate input length during utf8 conversion processes. When gmanedit processes a crafted man page containing specially constructed utf8 sequences, the open_man_file function does not adequately check buffer boundaries before copying data into heap-allocated memory regions. This improper memory management creates an opportunity for attackers to overwrite adjacent memory locations with malicious code payloads. The vulnerability is particularly concerning because it operates entirely within the application's normal processing flow, making detection and prevention more challenging for security monitoring systems.
The operational impact of this vulnerability extends beyond simple code execution, as it represents a privilege escalation vector that can be leveraged by remote attackers without requiring local system access. Attackers can craft malicious man pages that, when opened by a victim using gmanedit, trigger the buffer overflow condition and provide remote code execution capabilities. This scenario is particularly dangerous in environments where users may encounter untrusted documentation content, such as in shared computing environments or when browsing documentation from unverified sources. The vulnerability's ability to execute arbitrary code remotely through document processing makes it a significant threat to system security and user safety.
The security implications of CVE-2008-3971 align with CWE-121, which categorizes heap-based buffer overflow conditions as a fundamental memory safety issue. This vulnerability also maps to several ATT&CK techniques including T1059 for command and scripting interpreter and T1203 for exploit for client execution. The flaw's design allows for code execution through legitimate application functionality, making it a prime candidate for exploitation in targeted attacks. While the vulnerability description notes that another overflow exists in configuration file handling, that particular vector lacks privilege boundary crossing capabilities, making the man page exploitation scenario more severe from a security perspective.
Mitigation strategies for this vulnerability require immediate patching of the gmanedit application to address the buffer overflow in the utf8 conversion handling code. System administrators should ensure that all affected installations are updated to versions that properly validate input lengths during character encoding conversion processes. Additionally, implementing input validation controls and restricting user access to potentially malicious documentation content can help reduce the attack surface. Network segmentation and monitoring for unusual document processing activities may also provide early detection capabilities for potential exploitation attempts. Organizations should also consider implementing application whitelisting policies to prevent unauthorized versions of gmanedit from executing on systems.